[Autofill/Autocomplete Feature] Substring matching instead of prefix matching.

base/strings/string_util.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // This file defines utility functions for working with strings.
 
 #ifndef BASE_STRINGS_STRING_UTIL_H_
 #define BASE_STRINGS_STRING_UTIL_H_
 
 #include <ctype.h>
@@ skipping 482 matching lines @@
 // Returns true if the string passed in matches the pattern. The pattern
 // string can contain wildcards like * and ?
 // The backslash character (\) is an escape character for * and ?
 // We limit the patterns to having a max of 16 * or ? characters.
 // ? matches 0 or 1 character, while * matches 0 or more characters.
 BASE_EXPORT bool MatchPattern(const base::StringPiece& string,
                               const base::StringPiece& pattern);
 BASE_EXPORT bool MatchPattern(const base::string16& string,
                               const base::string16& pattern);
 
+// Returns offset to the beginning of first occurence of |search| in the |str|.
+// If no such subsequence is found, |base::string16::npos| is returned.
+BASE_EXPORT base::string16::size_type StartsAt(const base::string16& str,

[danakj, 2015/04/02 18:31:42]

why size_type and not size_t like everything else in this file?

[Pritam Nikam, 2015/04/06 06:13:10]

Done.

IMO, using size_type keeps it consistent for container data types. For
std::[w]string (here base::string16), std::[w]string::size_type is equal to
std::allocator<T>::size_type. But I guess its a typedef of std::size_t anyways,
so I'm restoring it to std::size_t.

+                                               const base::string16& search,
+                                               bool case_sensitive);
+
 // Hack to convert any char-like type to its unsigned counterpart.
 // For example, it will convert char, signed char and unsigned char to unsigned
 // char.
 template<typename T>
 struct ToUnsigned {
   typedef T Unsigned;
 };
 
 template<>
 struct ToUnsigned<char> {
@@ skipping 10 matching lines @@
 #elif defined(WCHAR_T_IS_UTF32)
   typedef uint32 Unsigned;
 #endif
 };
 template<>
 struct ToUnsigned<short> {
   typedef unsigned short Unsigned;
 };
 
 #endif  // BASE_STRINGS_STRING_UTIL_H_